Field of the Invention
Embodiments of the present invention generally relate to generating hierarchical binary structured light patterns and using such patterns in a structured light imaging device.
Description of the Related Art
In structured light imaging devices, a projector-camera pair is used to estimate the three-dimensional (3D) depth of a scene and shape of objects in the scene. The principle behind structured light imaging is to project patterns on objects/scenes of interest and capture images with the projected pattern. The depth is estimated based on variations of the pattern in the captured image in comparison to the projected pattern.
Structured light imaging devices can be broadly classified into two categories: single fixed pattern devices and dynamic multi-pattern devices. Dynamic pattern structured light imaging devices project several patterns with varying spatial frequencies, sweeping through the various patterns. The higher-frequency patterns can discern the finer details in the scene while lower spatial frequency patterns increase the range of depth values. Such a device generally requires that the scene be stationary during the entire capture process.
Fixed pattern structured light imaging devices project a single pattern on the scene and use a single captured image to estimate depth. Such devices are preferable when the objects in the scene are not stationary. These fixed pattern devices typically use a pattern with a single spatial frequency that is selected as a trade-off between capturing details in the scene and increasing the depth range, i.e., a higher spatial frequency pattern will capture details in the scene better whereas a lower frequency pattern will increase the depth range.